Semiclassical approaches to below-threshold harmonics

Journal Article · Sun Aug 15 04:00:00 EDT 2010 · Physical Review. A

DOI:https://doi.org/10.1103/PHYSREVA.82.023401· OSTI ID:21448518

Hostetter, James A; Tate, Jennifer L ^[1]; Schafer, Kenneth J; Gaarde, Mette B ^[1]

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1. Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803-4001 (United States)

We study the generation of below-threshold harmonics in a model atom by extending the three-step semiclassical model of harmonic generation to include effects of the atomic potential. We explore the generalization of semiclassical trajectories of the electron in the presence of the combined laser-atom potential and calculate the intensity-dependent dipole phase associated with these trajectories. Our results are in good agreement with fully quantum mechanical calculations, as well as with recent experimental observations. We show that the so-called long trajectory readily generalizes to below-threshold harmonic generation and is relatively insensitive to the choice of initial conditions. We also find that the short trajectory can only lead to low-energy harmonics for electrons that have been released close to the ion core in a process that is closer to multiphoton than to tunnel ionization.

• OSTI ID: 21448518
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 2 Vol. 82; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
APPROXIMATIONS
ATOMS
CALCULATION METHODS
CHARGED PARTICLES
DIPOLES
ELECTROMAGNETIC RADIATION
ELECTRONS
ELEMENTARY PARTICLES
FERMIONS
FREQUENCY MIXING
HARMONIC GENERATION
HARMONICS
IONIZATION
IONS
LASER RADIATION
LEPTONS
MECHANICS
MULTI-PHOTON PROCESSES
MULTIPOLES
OSCILLATIONS
POTENTIALS
QUANTUM MECHANICS
RADIATIONS
SEMICLASSICAL APPROXIMATION
TRAJECTORIES
TUNNEL EFFECT